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Nov
8
revised What does this Authentication protocol achieve and what information is shared?
transcribe protocol from image, tweak phrasing, remove thanks per site convention
Nov
8
reviewed Approve pseudo-random-permutation tag wiki excerpt
Nov
7
answered Is encrypting credit card numbers one by one with rsautl secure?
Nov
6
revised Security proofs for CBC mode
deleted 22 characters in body; edited tags
Nov
6
answered Security proofs for CBC mode
Nov
6
awarded  Popular Question
Nov
5
wiki created commutative-encryption description
Nov
5
wiki created commutative-encryption excerpt
Nov
5
revised Transparent cipher
edited tags
Nov
5
revised Software implementation of a commutative cipher?
edited tags
Nov
5
revised Are there any secure commutative ciphers?
edited tags
Nov
5
revised Can we decrypt in this order when the message is encrypted twice?
edited tags
Nov
5
reviewed Reject
Nov
5
reviewed Reject
Nov
1
comment If I have the unencrypted text and the encrypted text, can I calculate the key?
Related / near duplicates: crypto.stackexchange.com/questions/2949/… crypto.stackexchange.com/questions/3952/… crypto.stackexchange.com/questions/3832/… (and these are just the ones I've answered myself; I'm sure there are more)
Oct
28
comment Why are the initial states of hashes functions (like SHA-1) often non-zero?
@user8911: Typically, the kinds of things you may want to avoid are e.g. having the IV be equivalent to itself rotated by some number of bits, or perhaps reversed and/or inverted, or otherwise having some simple bit pattern that might make an attacker's work easier. A random IV is very unlikely to have such a pattern, but may raise suspicions if you can't explain why it was chosen; hence "nothing up my sleeve" numbers, which are supposed to be free of such patterns while still not having enough degrees of freedom to hide a back door.
Oct
27
comment Are there attacks that break collision resistance but not preimage resistance?
OK, great! I've remade the edits.
Oct
27
revised Are there attacks that break collision resistance but not preimage resistance?
rolled back to a previous revision
Oct
27
comment How can I prove/disprove that a construction yields a secure PRG?
Is the input space of your PRG really $\{0,1\}^*$? If so, what's the distribution of the inputs? (It can't be uniform, since there is no uniform distribution over $\{0,1\}^*$.)
Oct
27
revised What's the difference between the long term key and the session keys?
deleted 2 characters in body; edited tags; edited title